How do I increase the value of the Due Date field by a certain number of days ?

[Helen Porter]

Hi

There is an sql query that returns the number of days between two dates. We need to add this number of days to the Due Date field. How can this be done?
For example, the query result returns the value "4".
dueDate = dueDate + "xd";  => dueDate = dueDate + "4d"; 
How do I add this value in the sil script?